The aim of this study is to determine the physiological control of activation of the sympathetic nervous system, the renin angiotensin system and the antidiuretic - vasopressin system in patients with congestive heart failure. The influence of this activation of vasoconstrictor mechanisms on left ventricular function, regional blood flow, exercise tolerance and prognosis will be assessed. The effect of various pharmacologic interventions of these neurohumoral mechanisms will be studied and the relative efficacy of drugs administered to patients with different control neurohumoral states will be evaluated. The long-term goal of this study is to gain an understanding of how and why the tone of the peripheral vascular bed is altered in heart failure with the hope that therapy aimed specifically at inhibiting this vascular response may have a salutary effect on the natural history of the disease.